How Klingel has improved the quality of its customer database and reduced the number of postal returns and incorrect addressing


Daily events affect the quality of customer data. Current and accurate customer data is a requirement for good business. In this case, we highlight how Klingel is able to communicate more effectively and efficiently thanks to accurate and up-to-date customer contact data.

The Netherlands is constantly in motion; every year about 7% of all households relocate, thousands of people die and 3% of residents change surnames due to divorce or marriage. In addition, hundreds of thousands of postal code changes take place every year, caused by municipal reclassifications, renumbering and the construction or demolition of properties. Many organisations do not immediately realise that these events affect the quality of customer data.

For proper business operations, up-to-date and accurate customer data is a requirement. This also applies to webshop Klingel, part of Mail Order Finance GmbH. The organisation focuses on the online sale of women's and men's fashion, household items and home accessories, and operates in 13 countries.


Michael Labourel - Klingel:
"Our goal is to keep our database 'ACCU': Accurate, Correct, Complete and Unique. That way we can help our customers more effectively and save on returns due to incorrect addressing."

Due to its extensive range and international coverage, Klingel appeals to a large audience. The webshop has a lot of its own customer data. Keeping this information up-to-date is essential for effective customer communication. The challenge here is that the customer database changes daily due to events such as relocations and the passing away of loved ones.

Based on Klingel's needs, a quality check on the customer data was started. This included a quality analysis and baseline measurement. Attention was also paid to the timeliness and correctness of the customer data.


Before an organisation can start improving its data quality, it is important to know where it stands. For Klingel, a baseline measurement was therefore carried out first: mapping the current quality of the customer base. Together, an inventory was made of the available data and a data quality analysis was carried out on 100,000 records. This provided insight into the following elements, among others:

  • Spelling of surname
  • Correctness of addresses
  • Relocations
  • Deceased persons
  • Registration Do-not-call registry


Klingel maintains a mutation date in the customer file. This is the date on which a customer was last contacted. This date is used as a lead to check which data is the most up-to-date: Klingel's own customer data or EDM's reference data.

Michael Labourel: "Delivering the data was a time-consuming job for us, with a lot of internal contact, especially on our side, about how the file should be delivered. My advice is to coordinate this well in advance, also internally."

To determine the correctness of all of Klingel's customer data, after the test phase, Klingel's complete customer database was again compared with EDM's reference database. Various elements were used to test the extent to which the data was 'correct' and could be processed. The data that were scaled under the 'doubt' and 'uncertain' categories were checked manually.

Stefan Elsendoorn, data quality consultant at EDM: "By tightening the business ruling, only a small part of the customer database remained, which qualified for an additional manual check by Klingel employees."

Direct mailing to customer groups
To measure whether EDM's data quality solution yielded an improvement in the accuracy and actuality of customer data, Klingel chose to send a direct mail to its various customer groups. The number of mail returns were an important indication of the improvement.


One of the findings from the test phase was that there was a high number of deceased and a significant number of relocations. Based on these findings, the best approach for the remaining customer groups was determined and the initial impetus for the business ruling emerged.


As Klingel gained more insight into which postal items would not arrive at customers due to moves or deaths, they were able to make significant savings on printing and postage costs. In addition, postal returns fell from a total of 1.3% in 2018, to 0.27% in 2019.


With the improved data quality, Klingel has created a strong foundation to build on in the coming years, while also saving on unnecessary costs every year. The next step is the same data quality analysis for Klingel in Belgium; EDM offers data quality services in Belgium as well.

Michael Labourel: "We enjoy working with EDM. Communication is really good and the employees are always available. The start-up year was difficult, because we had to pass the file to be delivered internally by various people and this caused regular delays. This was not related to EDM. I am delighted!"

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